1. Field of the Invention
The present invention relates to a technology for displaying the pair state of a copy pair in one or a plurality of storage systems.
2. Description of the Related Art
For example, Japanese Patent Application Laid-Open No. 2004-264973 discloses a technology for copying data from a primary logical volume to a secondary logical volume which are paired. In to this patent application, the pair states of a plurality of volume pairs and the pair state of each volume pair are displayed in a list, as shown in FIG. 5.
Incidentally, a logical volume configuring a volume pair exists in one or a plurality of storage subsystems connected to a host computer. One logical volume and other logical volume may exist in a single storage subsystem or in separate storage subsystems.
As a configuration in which a plurality of volume pairs are used, the following configurations, for example, are possible. Specifically, possible are, for example, a configuration in which a copy group is obtained by synchronizing a plurality of volume pairs (see FIG. 1A), a configuration in which the primary logical volumes (referred to as “PVOL” hereinafter) of two volume pairs are the same (see FIG. 1B), and a configuration in which one secondary logical volume (referred to as “SVOL” hereinafter) and a PVOL are the same volume (see FIG. 1C).
In the case of such configurations of a copy group, even when employing a method of displaying the pair states of a plurality of volume pairs and the pair state of each volume pair in a list (see FIG. 2A, for example), a user viewing a screen displaying the list cannot understand whether the configuration using a plurality of volume pairs exists or not.
Therefore, as a method for solving such a problem, a method of displaying a pair state of an abstracted copy group, as shown in FIG. 2B, can be employed. In FIG. 2B, for example, at least one volume pair within a copy group, “G_DF600_SI”, is in a pair state of “sync”.
Furthermore, as another method, as shown in FIG. 2C, for example, a method of displaying a configuration of a plurality of volume pairs and a pair state of each volume pair can be employed. FIG. 2C shows a configuration of the example shown in FIG. 1C, and, as can be seen in the figure, the volume pair on the first row is in a pair state of “split” and the volume pair in the second row is in a pair state of “sync”.
As yet another method, a method of combining the display methods of FIG. 2B and FIG. 2C can be employed. Specifically, for example, as shown in FIG. 2D, a method of displaying a configuration consisting of a plurality of copy groups (for example, copy groups specified by a user) and a pair state of each copy group on a screen can be employed. According to FIG. 2D, for example, the pair state of a first copy groups is “sync”, the pair state of a second copy group is “split”, and the pair state of a third copy group is “resync”. According to FIG. 2D, each SVOL of the first copy group is integrated with each PVOL of the second copy group and of the third copy group.
However, even if any of the above-described methods is employed, at least the following three problems cannot be solved. Each of the problems is described hereinafter. It should be noted that a volume pair is referred to as “copy pair”. Further, a pair state which is not intended by a user is referred to as “involuntary state”, and, out of the involuntary pair states, an involuntary state which is required to be processed in any way (for example, a pair state which is changed due to detection of a hard error or soft error) is referred to as “error state”.
(1) Change of pair state, which is performed intentionally by the user, cannot be distinguished from other changes of pair states.
For example, when a copy pair of local copies (local copy is performed inside a single storage subsystem) is used, a user sometimes has to intentionally change the pair state of the copy pair in order to acquire a backup of data. Normally, change of pair state performed intentionally by the user should be distinguished from change of a pair state which is performed involuntarily by the user due to some kind of problems.
However, in the above display method, although a pair state is displayed on a display screen, it is not possible to distinguish, only by looking, whether the pair state is the one which is changed by an operation performed intentionally by the user. For this reason, the user cannot determine whether the pair state displayed on the screen is an intended result or an involuntary state which is not an intended result, and consequently has to distinguish the presence of a problem by collating an execution condition of the operation performed by the user himself with the displayed information.
(2) In the case where a number of copy pairs are in the error state, the scope of the occurrence of the error state is difficult to be comprehended.
Sometimes thousands of copy pairs exist in a single storage subsystem. All of these copy pairs or some batches of copy pairs are sometimes brought into the error state simultaneously, depending on the type of failure. For example, suppose that, in the case where thousands of copy pairs of remote copies (remote copy is performed in the case where a PVOL exists in a storage subsystem and a SVOL exists in other storage subsystem) are used, a failure occurs in a communication medium (for example, a cable or a switch) between the storage subsystems. In this case, all of the copy pairs (that is, copy pairs containing logical volumes into or from which data is input or output via the ports) that use the ports connected to the communication medium are brought into the error state due to this failure.
However, in the above display method, although the user can understand that the numbers of copy pairs are brought into the error state, since the displayed pair states of the numbers of copy pairs are changed to the error state, the user cannot take a panoramic view of the entire scope of the occurrence of the error state because the pair states are displayed in a copy pair unit or a copy group unit. For this reason, the user has to comprehend the entire scope of the occurrence of the error state by confirming the all copy pairs brought into the error state. Moreover, when displaying a number of pair states on the display screen and concurrently updating these numbers of pair states to the error state, there is a problem that it requires a long time to perform rendering of the screen, which is associated with updating of the information.
(3) When it is uncertain whether the pair state is the error state or not, the detailed information required for making determination is difficult to be comprehended.
A state to be detected as a pair state is changed to not only a pair state due to the above mentioned hard error, but also to a pair state due to an erroneous operation performed by the user. The erroneous operation performed by the user is not a detectable hard error or soft error, thus even if a pair state is changed by the erroneous operation of the user, the pair state is not displayed as the error state.
In other words, in the above display method, the user needs to determine whether the changed pair state is in the error state or not. Specifically, for example, in order to determine whether or not the changed pair state is in a state which requires to be processed (i.e. error state), the user has to perform another operation for displaying necessary detailed information and refer to the detailed information displayed by the operation.